The present invention relates to a method for operating a telecommunications network, in which a network element at a network node of the telecommunications network is controlled by a control computer. The network element is, for example, a switching office for switching links, what is referred to as a cross-connector or a concentrator unit for connecting a number of subscribers to a connecting line. In addition to the operating system for operating the control computer, a number of application programs, during whose execution application objects are processed, are stored in the control computer. The application objects are associated with data with a predefined data structure and preferably also predefined methods for processing the data. The data structure and the methods are dependent on a class which is also to be specified when the respective application object is generated. A link via which the control computer is maintained via maintenance messages is set up between a service computer and a control computer.
Such methods are used for controlling the telecommunications network if, for example, a new switching device is to be put into operation as a network element or if subscriber data in the switching device have to be changed at a later date, such as is the case when new subscribers are connected or when an existing subscriber moves. Efficient methods for controlling the telecommunications network are obtained if what are referred to as open systems are used which are programmed in compliance with standards which apply worldwide. For example, standards of the ISO (International Standardization Organization) and of the ITU (International Telecommunication Union) with its body the ITU-T, known earlier as the CCITT (International Telegraph and Telephone Consultative Committee) relate to the setting up of such open systems. A separate control network is to be used to control the telecommunications network. The interfaces between the service computer and switching device are standardized in protocols Q1, Q2 and Q3.
The application objects are defined as objects of an object-oriented language, for example in the language C++ or CHILL. If the application programs are developed, it is necessary to ensure that the control network also operates without faults with the new application programs. As such, in particular, application objects which are considered by the service computer as belonging to an original class cannot readily be assigned to an amended alternative class.
This problem is mentioned in the CCITT standard X.720 (01/92)—“Information Technology—Open Systems Interconnection—Structure of Management Information: Management Information Model”—in the section 5.2.1. In the section 5.2.3 of the standard X.720, two methods for solving the problem are proposed. In the first method, on the part of the application program, a programming technique is used which takes allomorphy into consideration. Allomorphy is the ability of a specific application object of the alternative class to be controlled as if it were an object of the original class if this ability arises as a result of measures on the part of the application program. The other method includes taking measures on the part of the service computer which permit cooperation between the service computer and the application program even when the application program is developed.
European patent application EP-A-0 817 422 discloses a method for implementing controlled objects in a subsystem of a controlled system in a network, at least one control system and one controlled system being present. The controlled objects are implemented independently of other subsystems without knowing the type of the objects in the other subsystems. They can be connected to other objects and can transmit messages to them. For this purpose, a first object is generated for cooperating with an abstract object. The abstract object has a defined interface which is called up using the first object and which inherits the abstract object from a second object, the generated second object being unknown to the first, and the second object being intended for cooperation with the first object. The first object which cooperates with the second object considers the second object as an object of the abstract type. However, in this method known from EP-A-0 817 422, there is no use of programming technology which takes into consideration the allomorphy in accordance with the section 5.2.3 of the standard X.720.
An object of the present invention, therefore, is to provide a simple method for operating a telecommunications network in which allomorphy is taken into consideration.